Mizuhopecten kanbaraensis (Otuka, 1938)
OTUKA, Y. 1938. Neogene fossils of the Ihara District, Sizuoka Prefecture, Japan. Journal of the Faculty of Science, Imperial University of Tokyo [Section II: Geology, Mineralogy, Geography, Seismology], 5 (1 & 2): 1-19, pls. 1, 2, text-figs. 1, 2. [p. 8, pl. 1, fig. 3]
1938 Patinopecten kanbaraensis Otuka, 1938
Y. Otuka, 1938, plate 1.
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«1926. Pecten yessoensis. YOKOYAMA Jour. Fac. Sci. Imp. Univ. Tokyo, sec. 2, 1, 7, p. 225 (not of JAY. 1856).
Holotype:— Only one right valve. Rg. No. 3987, E. R. I. Length 57 mm; heigbt 58 mm; thickness 6.3 mm. Paratype:— Three fragmental specimens. Type locality:— Siroyama sandstone at Siroyama, Kanbara town (Loc. C.)
Description:— Shell moderate size, rather thin, compressed, orbicular in outline, having same length and beight; right valve almost equilateral; external surface sculptured with radial ribs and fine concentric stria; ribs about 18, rounded unequal size, anterior and posterior of which are narrower than middle; ribs in middle part sometimes irregularly bifurcated; interspaces narrow, sharp: ears more or less large and vertically striated; dorsal hinge line straight; dorsal angle less than about 100°. Comparisons and affinities:— Patinopecten tokyoensis (TOKUNAGA) [5] is allied to this species. But the former has flattened ribs superimposed by some minor ribs. Patinopecten kimurai (YOKOYAMA) [6] is another shell allied to this, but the former species has more simple ribs, find fewer of them, than the latter. Patinopecten yessoensis (JAY) [7] is a species closely allied to this, but the former species has more flattened ribs, and more of them, than the latter species. The dorsal angle of the former species is about 120°, while that of the latter species is less than about 100°. Table 2 shows the geologic distribution of the subgenus Patinopecten DALL 1898 in Japan.
Distribution:— Siroyama sandstone at Kanbara town; Miocene (Tukiyosi beds) of Gihu pref. Geologic range:— Miocene.» YANOSUKE OTUKA, 1938
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